Separable casings or fuselage sections are utilized, for example, in rocketry for jettisoning burned out stages from the payload portion of a rocket or for deployment of a parachute to ease the descent of a store. Ideally, such a separable casing or fuselage section should be operated to provide a reliable separation with only straight line relative movement between the separated portions. Any tumbling movement imparted to either portion may cause damage to the rocket or a malfunction of the parachute deployed.
Disclosed in U.S. Pat. No. 3,032,356 (Botsford) is an explosive means for separating casing members. The device disclosed in this patent includes a tongue extending from the cover into a groove in the afterbody in which the explosive and pressure chamber are located. The tongue and groove arrangement has a metal to metal interface to contain the gases generated by the explosion and consequently the tolerances for these elements has to be closely controlled with a minimum clearance between the interfacing surfaces. It was found that small variations in tolerances changes the quality of the seal produced and changes the velocity of the ejected cover from one assembly to another.
The use of an obturator seal around an artillery shell to prevent the loss of gas pressure during firing of the shell is also known in the prior art. These obturator seals are formed of white rigid plastic and the gas pressure forces the edge of the ring out against the barrel.